The invention herein relates to truss-like fabricated joists or beams made of wood chords preferably interconnected by metal web units or struts. This type of beam is disclosed in my earlier U.S. patent application Ser. No. 893,317, filed Apr. 3, 1978, now U.S. Pat. No. 4,207,719 and identified as a "Composite Construction Beam".
In the construction of houses and other relatively small buildings, it is conventional to use solid wood beams for floor joists, ceiling supports, roof joists and the like. Generally such beams have nominal cross-sectional dimensions of 2.times.6, 4.times.8, 4.times.10, 4.times.12, etc. (inches). However, due to increased demand and decreasing availability of high grade lumber, the prices of lumber needed for making such beams have risen. Consequently, my earlier application Ser. No. 113,171, now U.S. Pat. No. 4,308,703, and the subject matter of this application are concerned with fabricated type beams which are made of more readily avilable, less expensive, smaller cross-section lumber, such as 2.times.4's, which lumber is interconnected with metal struts, and where the wooden members are interconnected by angled metal staples or fasteners.
The use of wood strips, interconnected by sheet metal web units or struts to fabricate trusses is known. Examples of such trusses are illustrated in the prior art U.S. patent to Sanford, No. 3,416,283, issued Dec. 17, 1968, and in my earlier U.S. Pat. No. 4,002,116, issued Jan. 11, 1979 and No. 4,078,352, issued Mar. 14, 1978. However, these prior trusses are, in general, more expensive and ordinarily must be designed with a greater height-to-span ratio than is contemplated for the use of the present beam type, that is, for the substitution of a fabricated truss-like beam for solid wood beams.
In accomplishing the fabricated beam construction herein, it is contemplated to utilize additional wood strips interposed between the wood chords for shear load absorption. The use of wood pieces between chords of a truss, in addition to the use of webs or struts, is known, for example, as disclosed in U.S. Pat. No. 3,748,809 issued to Jackson on July 31, 1973 and in Swiss Pat. No. 306,573, of Apr. 30, 1955 to Kampf. However, shear force absorption and resistance to bending are too limited by the constructions disclosed in those patents.
It is also known to use metal fasteners, nails, wire or the like to secure parts together as illustrated, for example, in the aforementioned patent to Jackson, Australian Pat. No. 247,162 of 1961 to Dixon, and French Pat. No. 667,419 of 1929, to Schaub.
None of the aforementioned patents are directed to the problem of the increased cost of lumber, nor the solution of using less expensive, lower grade, smaller cross-section lumber, with the use of fasteners and/or metal struts, to make a beam which will support the loading requirements of beams formerly made of higher grade, larger cross-section lumber.
For example, U.S. Pat. No. 3,748,809, issued to Jackson on July 31, 1973, illustrates a joist structure where metal fasteners are used to secure metal tension members to the chords of the joist. There is no teaching or suggestion of the use of face entry metal fasteners, inserted at an angle, to secure wooden members together to absorb shear loads, resist bending, resist relative slippage of the wooden members, or to self-energize the fastener under loading conditions to increase the friction between the wooden members, or for angling the fasteners upwardly toward the nearest beam end, all of which permit lower grade, smaller cross-sectional lumber to be used in a beam.
Australian Pat. No. 247,162, to Dixon, published Jan. 26, 1961, illustrates a joist where the apex joint, i.e., the joint where the loading and compressive forces neutralize each other, may be lightly held together by a nail inserted at an angle or alternatively by horizontal, face entry corrugated fasteners. There is no teaching or suggestion of the use of face entry metal fasteners, inserted at an angle, to secure wooden members together to absorb shear loads, resist bending, resist relative slippage of the wooden members, or to self-energize the fastener under loading conditions to increase the friction between the wooden members, or for angling the fasteners upwardly toward the nearest beam end, all of which permit lower grade, smaller cross-sectional lumber to be used in a beam.
The French Pat. No. 667,419 issued in 1929 to Schaub illustrates a composite concrete and wooden member having a tongue and groove arrangement therebetween, where metal fasteners such as nails or screws are embedded in both the concrete and wood. Again, there is no teaching or suggestion of the use of face entry metal fasteners, inserted at an angle, to secure wooden members together to absorb shear loads, resist bending, resist relative slippage of the wooden members, or to self-energize the fastener under loading conditions to increase the friction between the wooden members, or for angling the fasteners upwardly toward the nearest beam end, all of which permit lower grade, smaller cross-sectional lumber to be used in a beam.